Centrifugal starter for electric motors



' 1,682,424 M. SCHIESSER CENTRIFUGAL STARTER FOR ELECTRIC IOTORS Filed Jim. 13, 1925 Au 2a, 192&

' resistance of a spring.

Patented Aug. 28, 1928.

UNITED STATES 1,682,424 PATENT oFFlcE.

BROWN, BOVERI .AIND CIR,

OF IBADEN, SWITZERLAND.

CENTRIFUGAL STARTER FOB. ELECTRIC MOTORS.

Application filed January 13, 1925, Serial No. 2,189, and in Germany January 26, I924.

Centrifugal starters for electric motors with rotating strating resistances have been known, the movable contacts of which themselves form the centrifugal weights and at a predetermined angular velocity are pressed upon the stationary contacts against the One of these known constructions exhibits as its special characteristic the decrease in the distance between the axis of the spring and the axis of ro-,

- fore, counter-weights are arranged on a sec- .ond arm of the contact lever, and these counter-weights serve to relieve the springs, so that they may be constructed weaker. This may be carried so far that the contact lever is completely counter-balanced, and for the demands of the apparatus only the centrifugal force of the springs is the determining factor.

In the drawing are illustrated in longitudnial section two constructional examples of the invention; in this'drawing 1 denotes the motor shaft, 2 the carrier, secured to the shaft, for the contact device, 3 the stationary contacts, 4 the movable contact arms, which are rocliable about the pivot 5 and which, by the position thereof, become the twoarmed lever, with the contact iece 7 secured to the yielding support 8, and 9 the spring. In addition there is the, counter-balancing weight 10, which according to Figure 1 is specially mounted on the short arm of the contact lever 4, but in the example according to Figure 2 is formed by the short lever arm itself, and there serves also as a point of attachment for the spring 9.

In the case of Figure 2 the spring 9 engages at the bent-up end of the otherwise straight lever t.

What I claim is 1. A centrifugal switch for mounting on a lever pivotally mounted on said bell-shaped body at a point away from the closed end thereof, a spring supported at said closed end and acting on one arm of said lever, a contact member on the other arm of said lever arranged to move with said arm outwardly under the actionof the centrifugal force in opposition to the action of said spring, the pivotal mountin of said arm causing said movement to e in a plane through the shaft, and contact members on said bell-shaped body adapted to be engaged by the contact member of said lever arm, the mass of the movable contact member and the associated lever arm being substantially counter-Weighted by the mass associated with the otherarm of said lever.

2. In a centrifugal switch, a hub member adapted to be mounted on a shaft, a bellshaped cylinderextending from said hub member and overhanging the same to define a cylindrical hollow space between said hub member and said cylinder, a bell crank lever supported near the open end of said cylinder for pivotal movement in a plane through said shaft, one arm of said lever being disposed toward said hollow space, aspring supportedfrom the closed end of said bellshaped cylinder to press said arm toward said hollow space, a stop on said hubmember for' limiting the movement of said arm to ward said hollow space, a moving contact member on the. other arm of said lever arranged to move-outwardly under the action of the centrifugal force in opposition to the action of the spring on said first-mentioned arm, and stationary contact members onsaid cylinder adapted to be engaged by said moving contact member, said arms being so arranged'with respect to the pivotal support thereof that the centrifugal force "acting on the mass of the moving contact member and the assoclated arm 18 substan-v tially counter-balanced by the centrifugal force acting on the mass associated with the M. SCHIESSER, 

